Dial switching toll system



P 15, 1931. 'r. s. SKILLMAN ET AL 1,823,333

DIAL SWITCHING TOLL SYSTEM Filed Nov. 12, 1930 57 T El W E! E M 0T TSF f Y Y INVENTORS 7:5.5K/LLMAN LGFREETH By RJBERRV @fiM A T TORNEV Patented Sept. 15, 1931 UNITED STATES rarest OFFICE THOMAS SAMUEL SKILLMAN, LANCELO'I GERI'IARD FREETH, AND ROBERT JAMES BERRY, OF ALDWYCH, LONDON, ENGLAND, ASSIGNOBS TO WESTERN ELECTRIC COM- PLANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK DIAL SWITCHING TOLL SYSTEM .App1ication filed November 12, 1930, Serial No. 495,199%, and in Great Britain November 13, 1929.

v This invention relates to telephone systems in which automatic switches are used in the establishment of connections and more particularly but not exclusively to such systems 5 in which facilities are provided for extending connections over toll lines.

The object of the invention is to provide in a system of this character more efiicient means whereby toll calls may be automatqym ically established without the services of operators in the order in which the calls arrive. It has been the practice in the past for toll calls to be extended by an operator 'at a toll exchange. A calling subscriber requiring a toll connection asks the A operator for the required number or alternatively for the toll exchange and he. is thereupon switched through by way of a recording trunk to the go toll exchange where :the recording operator writes out a ticket giving the numbers of the i wanted and calling parties and passes it to the toll operator in charge of the toll line leading to the requiredexchange. The calling party is then instructed to hang up.

During slack periods the toll operator can immediately ring through to the distant operator on the toll line and ask for the wanted number. During rush hours all the trunks at the toll operators position will be engaged and the ticket is added tothose already awaiting their turn. When, however, the toll Operator has asked fora wanted number over a trunk she then calls back to the calling subscriber over a toll switching trunk and if the wanted subscriber has replied she connects the two parties. I

The above method necessitates a considerable amount of work for each connection on the part of the toll operator and in consequence such operators can only deal with a very limited number joftoll calls. It followstherefore that the operating costs are high and the operating efliciency low.

It has also been proposed to use" a full automatic switching equipment for the establishment of toll connections in which for example the calling subscriber I dials the wanted number into a local register sender, which upon having stored the said single call or part thereof, tries to extend th ll 1507a toll line leading to the desired exchange. It will readily be understood by those skilled in the art, that in order to prevent difficulties in handling such calls, such as delays during rush hours, it will be necessary to provide an adequate number of toll lines out-going in the desired directions. The number of lines must be such that the local connecting circuit to which the register is attached during the setting up of the connection can readily find access to a toll line and in consequence will not hold the local register sender in use for a long period. For these reasons the number of toll lines should be adapted to the maximum number of calls outgoing in a particular dione embodiment of which is disclosed herein by way of illustration, the delay and expense incident to the employment of operators for establishing toll connections in an automatic exchange area is obviated. The invention has been illustrated by the single figure of the accompanying drawing. It should be under stood, however, that the invention and the variousfeatures thereof is not limited to this particular embodiment but may be applied to any telephone or remote control system in which the connections are established by means of automatic switching apparatus. It should also be understood that only such parts of the system are shown in the drawing and described hereinafter as are absolutely necessary for a clear understanding of the local equipment shown on'he letthand side of the drawing and comprising the switch LF and selector OS, the register selector RS and the registering mechanism R form no part'of the present invention and may be of any suitable type. For example the calling line may be connected to the brushes of a prethe called subscribers number.

selector and the local registering mechanismmay be dispensed with.

As soon as an idle registering mechanism has been selected, and is ready to take up the series foii impulses representing the toll call designation, a dialing tone is transmitted to the calling subscribers station. As the calling subscriber desires a toll connection he will first dial a prefix indicating such a connec tion. This prefix may comprise three digits such as TOL or TRU. When this prefix has been received by the local registering mechanism this registering mechanism will immediately start tooperate the selector switch OS to select a free trunk leading to the toll exchange. In the case under consideration the subscriber will be instructed to dial only said prefix and to await a second dialing tone which will be given as soon as a line finder such as FS' has picked up the calling trunk and connected thereto an auxiliary register sender mechanism TR. The calling subscriber thereupon dials the wanted subscribers number, for example, MAN 8312 and follows it immediately by his own number,

eating a toll call has been received in the,

local registering mechanism R. This prefix will cause a finder switch to hunt for that particular registering mechanism and to connect it with the said auxiliary register- 7 ing mechanism in which the surplus of digits maybe stored. The auxiliary registering Vmechanism and the circuit arrangements in the local registering mechanism may be similar to that disclosed in the application of O.

Stevens and M. den Hertog Serial No.

459,331, filed June 5,1930.

It will be assumed, however, that only the *toll prefix will be stored in the local registermechanism R. Inthis case this registering *mechanism starts the selection of a free trunkthrough-the operation of selector OS immediatelyafter the second digit has been received and stored therein. This selection is carried out in the well known manner and need not be described herein. It should be noted, however, thatalthough only one selector OS in'the originating ofiice has been disclosed for extending. a connection to the desired toll exchange, shown in the drawing,

this connection may be established over a plurality of such selectors as is well known in the art, the number of such selectors being determined by the particularcircumstances.

As soon as a connection has been extended by a selector OS in the originating exchange to a trunk line outgoing to the toll exchange,

I a line finder FS is started'to hunt for the calling or outgoing trunk line in a well known manner. When said trunk line. has been found, a dialing tone is transmitted t o'the calling subscriber from the auxiliary registering mechanism TR and the subscriber will thereupon proceed with the dialing operation. In the meantime the local link circuit has been connected through the switchj-OS and thence to the outgoing trunk circuit and therefore the impulses dialed by the calling subscriber will be transmitted directly to said auxiliary registering mechanism TR. For this purpose suitable impulse repeating devices of any well known construction may be arranged in the local link circuit. j

The auxiliary registering mechanism TB is so arranged that the seriesof impulses representing the wanted subscribers number are received by a translating registering device which maybe of any well known type. Means are also provided therein whereby on the completion of the registering of the wanter subscribers number a change over is effected to route the series or impulses'representing the calling subscribers number to another registering device. This latter device may be a straightforwardstep-by-step register or a register in which switches are caused to hunt under the control of a counting relay chain inith'e well knownmanner. The auxiliary registering mechanism TB is further equipped with atime alarm switching mechanism which operates if any delay occurs or only a partial call is set up. This H time alarm switching mechanism when operated causes the immediate release of the auxiliary registering mechanism TR and the local connecting circuits. The circuit arrangement, however, may be such that upon the release of the auxiliary registering mechanism, the subscriber'isconnected through to an operator in the well known manner. If, however, a complete call has been setup,

that is if the complete designations of the called and calling parties have been stored in the register the auxiliary registering circuit starts to secure access. over a selector SS and a trunk-ST to a punching mechanism PM which is individual to a group of tolllines incoming to the required toll. exchange or to an intermediate switching exchange required for the call; Each-auxiliary registering mechanism TR has access to one such trunk ST only for each group'of outgoing toll lines;

The punching mechanism PM is of the type used in telegraph systems which punches upon a tape T or a card a series 01": holes forming a record of the call. The operating speed of this punching mechanism is very high and it is therefore possible to discharge the auxiliary registering mechanism TR after a very shortinterval. Therefore one such mechanism PM will'suthce for the whole of the calls and to serve a small group of trunks. In cases where large groups of trunks are available, a distributing mechanism DM which may conveniently consist of a group of relays is provided to allocate a number of punching mechanisms suchas PM, PM, P M toincoming calls in turn. After a record of the call has been punched upon the tape T by the punching mechanism PM and the auxiliary registering mechanism TR has been discharged, no apparatus in the originating ofliceismaintained on the connection, except theline switches'LF and FS, the selector OS and the switch SS;

The tape T or the card on which the designationsvof the called and the calling parties have been stored, is fed through a sending mechanism SM which isindividual to the required group oftoll lines and which is arranged to beconnected to a toll line over a switch TS immediately one becomes free. Associated with each toll line is a connecting mechanism CM which consists of suitable switching and signaling relaysfor receiving andtransmitting signals over the tool line. Each such mechanism is associated with a hunting switch TSF which is arranged to pick up a toll switching trunk immediately the connecting mechanism" CM is seized.

Located at a monitoring operators position OPM is a pri'nting mechanism of the type used in printing telegraph systems which prints upon a tape the digits of the numbers of the calling and called parties retransmitted by the sending mechanism SM under control of the tape T. The record thus printed serves as a charge ticket for the established toll connection. The impulses transmitted by the sending mechanism SM corresponding to the called partys number also pass through the connecting mechanism CM and are recorded in the registering mechanismR local to the called partys exchange, saidregistering mechanism being associated with the connecting mechanism CM through the operation of the line finder TC and a register selector RS.

At'the conclusion of the transmission of the digits of the wanted partys number a change-over is'effected by the mechanism CM preferably by means of, a changeover signal punched on the tape T and the remaining impulses recorded on the tape are sent out over the switch TSF and the toll switchingtrunk and the outgoing toll switch CT to connect up the calling subscriber by means of the local automatic switching" apparatus, LS LS and FL. Thereafter the sending mechanism SM is immediately released and the mechanism CM awaits response by the two subscribers.

At the called partys exchange, when the toll trunk line has been extended thereto through the connecting mechanism CM, the line finder TC associated with the link circuit CO is started to find the calling toll line and a register sender selector RS associated with said link circuit selects an idle registering mechanism R As soon as the selecting mechanism R becomes associated a signal is transmitted to the sending mechanism SM to cause it to start the retransmission of impulses corresponding to the called partys number to the registering mechanism R followed by the retransmission of impulses for selecting the calling partys line. By means of a simple relay device in the link circuit CC a signal is operated before the monitoring operator MO. The impulses received by the registering mechanism R are effective in the well known manner to set a train of switches, one of which is shown at C to extend the toll connection to the wanted partys line.

In the event of the called subscriber being busy, a relay is operated in the link circuit CO and as a result a signal is sent over the toll line which actuates a device at the connecting mechanism CM to attract the attention of themonitoring operator at OPM. The monitoring operator llSJOHS in on the connection, hears the busy tone and promptly rings'over the toll line to obtain the attention of the ouerator MO and then requests her to otter the call to the wanted subscriber whose number can be readily obtained from the typed tape at the printer of position PM. If the called subscriber is busy, a busy flash relay in theconnecting mechanism CM is operated and the operator at the positionOPh/l is brought in on the connection as before. The operator at position CPM now rings up the calling subscriber to inform him that the called subscriber is busy and thereupon the release of the connection takes place in the well known manner. I

The record on the tape at the operators position 0PM gives a complete record of the call and a record of the total number of calls over a particular toll line and enables the operator to make notes regardinga call actually being recorded upon the tape and finally permits the station called and the condition of the toll line that is busy or free to be readily observable from the monitoring operators position OPML In accordance with a modification of the present invention arrangements might also be made whereby a subscriber could obtain toll dialing facilities only by first dialing his own number, such calling subscriber being subsequentlyrecallcd over a train of switches which provides the toll dialing facilities. In accordance with a further modification of the invention, thecalling sub scriber' might not be required to dial his own number, suitable arrangements being provided whereby a record of his number could be set up in the register TR by sending or other suitable mechanism, the operation of which would be. determined by the position of the calling line in the bank of the line finder switch LF.

hat is claimed is:

1. In an automatic telephone system, calling lines, called lines, automatic switching devices for extending connections to said called lines, a storing mechanism for storing the designations of called lines in the order in which calls therefor are initiated by said calling lines, and a sending mechanism individual to said storing mechanism for successively controlling said switching devices in accordance with the designations stored in said storing mechanism.

2. In an automatic telephone system, calling lines, called lines, automatic switching devices for extending connections to said called lines, a storing mechanism for storing the designations of called lines in the order in which calls therefor are initiated by said calling lines, and a sending mechanism individual to said storing mechanism effective for controlling said switching devices in accordance with the designation of one called line stored in said storing mechanism while 7 ing lines, called lines,

said storing mechanism is successively storing the designations of called lines for later initiated I calls.

3. In an automatic telephone system, call automatic switching devices for extending connections to said called lines, a storing iechanism comprising a tape and a tape punching device for storing the designations of called lines in the order in which calls therefor are initiated by said calling lines, and a sending mechanism individual to said storing mechanism for successively controlling said switching devices in accordance with the designations punched in said tape.

a. In an automatic telephone system, calling lines, called lines, a storing mechanism for recording the designations of calling and called lines, a sending mechanism, switching devices for extending connections in opposite directions to a calling line and to a called line and means under the control of said storing and sending mechanisms for operating said switching devices.

5. In an automatic telephone system, calling lines, called lines, a storing mechanism for recording the designations of calling and 7 called lines, means controlled by successively calling lines to seize said storing mechanism and to cause said storing mechanism to successively record the designations of said calling lines and the designations of called lines calledthereby, a sending mechanism, switch.- ing devices for extending connections in 0pposite directions to calling lines and called lines called thereby, and means under the control of said sending mechanism. for operating said switching devices to establish connections between said calling and called lines in the order in which said line designations have been stored in said storing mechanism.

6. In an automatic telephone system, calling lines, called lines, a storing mechanism for recording the designations of'calling and called lines, means controlled bysuccessively calling lines to seize said storing mechanism and to cause said storing mechanism to sue cessivelyrecord the designations of said calling lines and the designations of called lines called thereby, a sending mechanism, switch ing devices for extending connections in opposite directions to calling lines and called lines called thereby, and means under the control of said sending mechanism for operating said switching devices to establish 'a connection between a calling line and-a called line .in accordance with a record stored in said storing mechanism, while said storing mechanism is effective to store "the record of a subsequently initiated call. v

7. In an automatic telephone system, calling lines, calledlines, a-storing mechanism comprising a tape and Ya tape punching device for storing the designations'of calling and called lines, means controlled by successively calling lines to seize said storing mechanism and to cause said punching device to successively punch in said tape the designations of said calling lines and the designations of called lines called'thereby, a sending mechanism individual to said-stop ing mechanism, automatic switching devices for extending-connections in opposite direc tions to calling lines and called lines called thereby, and means controlled by said sending mechanism for successively controlling said switching devices in accordance with the designaiions punched in said tape.

8. In an automatic telephone system, calling lines, called lines, automatic switching devices for extending connections to said called lines, a storing mechanism for storing the designations of called lines in the order in which calls therefore are initiated by said calling lines, a sending mechanism individual to said storing mechanism for successively controlling said switching devices in accordance with the designations stored in said storing mechanism, a' monitoring operators position, and means at saidposition under the control of said storing mechanism for making a printed record of the designations of called lines in the ordercin which connections are established by said sending mechanism.

9. In an automatic telephone system, calling lines, called lines, a storing mechanism for recording the designations of calling and called lines, means controlled bysuccessively posite directions ,to calling lines and called lines called thereby, means under the control of said sending mechanism to operate said switching devices to establish connections between calling and called lines in the order in which said line designations have been stored in said storing mechanism, a monitoring operators position and means at said position under the control of said storing mechanism for making a printed record of the designations of calling lines and the lines called thereby.

10. In an automatic telephone system, calling lines, called lines, a storing mech anism for recording the designations of calling and called lines, means controlled by successively calling lines to seize said storing mechanism and tocause said storing mechanism to successively record the designations of said calling lines and the designations of called lines called thereby, means for disconnecting a calling line from said storing means as soon as the designations appertaining to the call initiated by said cal ing line have been stored, a sending mechanism, switching devices for extending connec ions in opposite directions to calling lines and called lines called thereby, and means under the control of said sending mechanism for operating said switchin I devices to establish connections between ca ling and called lines in the order in which said line designations have been stored in said storing mechanism.

11. In an automatic telephone system, calling lines, called lines terminating in a toll ofiice, toll lines incoming to saidoflice, automatic switching devices in said otlice for extending connections from said toll lines to said called lines, a storing mechanism for recording the designations of toll cords initiated by said calling lines for said called lines in the order in which said calls are initiated by said calling lines, a sending mechanism individual to said storing mechanism, means for associating said sending mechanism with said toll lines as fast as said toll lines become free, and means effective upon the successive association of said sending mechanism with free toll lines for controlling said switching devices in accordance with the toll call designations recorded by said storingmech anism and in the order in which said designations have been recorded.

12. In an automatic telephone system, calling lines, called lines terminating in a toll ofiice, toll lines incoming to said oflice, automatic switching devices in said office for eX- tending connections from said toll lines to said called lines, automatic switching devices for extending connections from said toll lines to said calling lines, a storing mechanism for recording the designations of toll calls initiated by said calling lines, said designations includin the designations of said calling lines and the designations of the called lines called thereby, a sending mechanism individual to said storing mechanism, means for associating said sending mechanism with said toll lines as fast as said toll lines become free, and means effective upon the successive association of said sending mechanism with freetoll lines for controlling said switching devices in accordance with the toll line designations re- "corded by said storing mechanism to establish connections between said calling and called l1nes 1n the order in which said deslgnations have been recorded.

13. In an automatic telephone system, call- H ing lines, terminating in a local office, called lines terminating in a toll oifice, toll lines out going from said local oilice, means in said local ofiice responsive to the dialing of a toll ooiiice code for extending connect1on's from calling lines to outgoing toll lines, toll lines incoming to said toll ofiice, automatic switching devices in said toll oflice for extending connections from said toll lines to said called lines, automatic switchin devices for extend ing connections from said incoming toll lines to said calling lines, toll call designation recording means associable with said outgoing toll lines, a storing and sendin mechanism successively associable with said recording means and with said incoming toll lines, and means controlled by said storing and sending mechanism for successively establishing connectionsbetween calling and called lines in accordance with the designations set up in ing lines terminating in a local oiiice, caller lines terminating in a toll office, toll lines outgoing from said local oflice, means in said local ofiice for extending connect1ons from calling lines to outgoing toll lines, toll lines incoming to said toll oifice, automatic switching devices in said toll office for extending connections from said toll lines to said called lines, automatic switching devices for extending connections from said incoming toll lines cording means associable with said outgoing toll lines, a storing and sending mechanism successively associable with said recording means and with said incoming toll lines,

tosaid calling lines, toll call designationremeans controlled by said recording means to transfer said toll call designations to said storing means, means operative following the transfer of a designation for releasing I the connection between a calling line and the particular recording means associated there- .with, and meanscontrolled by said storing and sending mechanism for successively establishmg connections between calllng and called lines in accordance with designations calling lines, called lines, a plurality of storing mechanisms for recording the designations of calling and called lines, means controlled by successively calling lines to seize $3,161 storing mechanisms in rotation and to cause said storing mechanisms to successively record the designations of said calling lines and the called lines called thereby, a sending mechanism individual to each storing mechanism, switching devices for extending connections in opposite directions to calling lines and called lines called thereby, and means under the control of a sending mechanism for operating said switching devices to establish connections between calling and. called lines-in the order in which line designations have been stored inthe storing mechanism to which it is individual.

16, In a telephone system in which connections are established between subscribers lines by means of automatic switching mechanism, the method of handling calls initiated by subscribers for distant toll points which consists in automatically punching a tape under-the remote control of the calling subscriber listing thenuinber of the line wanted and the number of the calling line, and auto- ;matically controlling said switching mechanism in accordance with the record punched. in said tape to extend a connection from a toll line in opposite directions to said calling line-and to said wanted line. v

17 i In a telephone system in which con nections are established between subscribers lines by means of automatic switching mechanism, the method of handling calls initiated by subscribers for distant toll points which consists in automatically punching a tape under the remote control of the calling subscriber listing the number of the line wanted and the number of the calling line, automatically controlling said switching mechanism in accordance with the record punched in said tape to extend a connection from a toll line in opposite directions to said calling line and to said wanted line and automatically printing a toll ticket under the control of said tape.

18 In. a telephone system in which connections are established between subscribers lines by means of automatic switching mechanism, the method of handling calls initiated bysubscribers for distant toll points, which consists in automatically punching actape under. the remote control of calling subscribers to successively record the data of the successively initiated toll calls, data for each call comprising the number of the line wanted and the number of the calling line, feeding said tape intoa sending mecha- ,nism, and successively controlling said sending mechanism under the control of said tape to extend toll connections between calling and called lines over said switching mechanism the order in which said toll calls were initiated.

In witness whereof, we hereunto subscribe our'names this 14th day of October, 1930.

THOMAS SAMUEL SKILLMAN. LANCELOT GERHARD FREETH. ROBERT JAMES BERRY. 

